"Historic times call for historic decisions," Mette Frederiksen told a press conference, adding that the government "very clearly calls on Danes to lift the opt-out on defence".

Denmark's opt-out, one of four EU special arrangements negotiated by the Scandinavian country, sees it abstain from participation in EU military operations and from providing support or supplies to EU-led defence efforts.

On Sunday Frederiksen also pledged to increase the country's defence spending to two percent of GDP, in line with NATO membership requirements, by 2033, calling it the "largest investment in recent decades".

The Social Democrat leader also expressed a wish to make Denmark "independent of Russian gas", but did not specify a time frame.